patch-2.1.8 linux/include/linux/tty_ldisc.h

• Lines: 102
• Date: Thu Nov 7 19:51:20 1996
• Orig file: v2.1.7/linux/include/linux/tty_ldisc.h
• Orig date: Mon Sep 30 11:19:00 1996

diff -u --recursive --new-file v2.1.7/linux/include/linux/tty_ldisc.h linux/include/linux/tty_ldisc.h
@@ -2,7 +2,100 @@
 #define _LINUX_TTY_LDISC_H
 
 /*
- * Definitions for the tty line discipline
+ * This structure defines the interface between the tty line discpline
+ * implementation and the tty routines.  The following routines can be
+ * defined; unless noted otherwise, they are optional, and can be
+ * filled in with a null pointer.
+ *
+ * int	(*open)(struct tty_struct *);
+ *
+ * 	This function is called when the line discpline is associated
+ * 	with the tty.  The line discpline can use this as an
+ * 	opportunity to initialize any state needed by the ldisc routines.
+ * 
+ * void	(*close)(struct tty_struct *);
+ *
+ *	This function is called when the line discpline is being
+ * 	shutdown, either because the tty is being closed or because
+ * 	the tty is being changed to use a new line discpline
+ * 
+ * void	(*flush_buffer)(struct tty_struct *tty);
+ *
+ * 	This function instructs the line discipline to clear its
+ * 	buffers of any input characters it may have queued to be
+ * 	delivered to the user mode process.
+ * 
+ * int	(*chars_in_buffer)(struct tty_struct *tty);
+ *
+ * 	This function returns the number of input characters the line
+ *	iscpline may have queued up to be delivered to the user mode
+ *	process.
+ * 
+ * int	(*read)(struct tty_struct * tty, struct file * file,
+ *		unsigned char * buf, unsigned int nr);
+ *
+ * 	This function is called when the user requests to read from
+ * 	the tty.  The line discpline will return whatever characters
+ * 	it has buffered up for the user.  If this function is not
+ * 	defined, the user will receive an EIO error.
+ * 
+ * int	(*write)(struct tty_struct * tty, struct file * file,
+ * 		 const unsigned char * buf, unsigned int nr);
+ *
+ * 	This function is called when the user requests to write to the
+ * 	tty.  The line discpline will deliver the characters to the
+ * 	low-level tty device for transmission, optionally performing
+ * 	some processing on the characters first.  If this function is
+ * 	not defined, the user will receive an EIO error.
+ * 
+ * int	(*ioctl)(struct tty_struct * tty, struct file * file,
+ * 		 unsigned int cmd, unsigned long arg);
+ *
+ *	This function is called when the user requests an ioctl which
+ * 	is not handled by the tty layer or the low-level tty driver.
+ * 	It is intended for ioctls which affect line discpline
+ * 	operation.  Not that the search order for ioctls is (1) tty
+ * 	layer, (2) tty low-level driver, (3) line discpline.  So a
+ * 	low-level driver can "grab" an ioctl request before the line
+ * 	discpline has a chance to see it.
+ * 
+ * void	(*set_termios)(struct tty_struct *tty, struct termios * old);
+ *
+ * 	This function notifies the line discpline that a change has
+ * 	been made to the termios stucture.
+ * 
+ * int	(*select)(struct tty_struct * tty, struct inode * inode,
+ * 		  struct file * file, int sel_type,
+ * 		  struct select_table_struct *wait);
+ *
+ * 	This function is called when a user attempts to select on a
+ * 	tty device.  It is solely the responsibility of the line
+ * 	discipline to handle select requests.
+ *
+ * void	(*receive_buf)(struct tty_struct *, const unsigned char *cp,
+ * 		       char *fp, int count);
+ *
+ * 	This function is called by the low-level tty driver to send
+ * 	characters received by the hardware to the line discpline for
+ * 	processing.  <cp> is a pointer to the buffer of input
+ * 	character received by the device.  <fp> is a pointer to a
+ * 	pointer of flag bytes which indicate whether a character was
+ * 	received with a parity error, etc.
+ * 
+ * int	(*receive_room)(struct tty_struct *);
+ *
+ * 	This function is called by the low-level tty driver to
+ * 	determine how many characters the line discpline can accept.
+ * 	The low-level driver must not send more characters than was
+ * 	indicated by receive_room, or the line discpline may drop
+ * 	those characters.
+ * 
+ * void	(*write_wakeup)(struct tty_struct *);
+ *
+ * 	This function is called by the low-level tty driver to signal
+ * 	that line discpline should try to send more characters to the
+ * 	low-level driver for transmission.  If the line discpline does
+ * 	not have any more data to send, it can just return.
  */
 
 #include <linux/fs.h>